I don't understand why people think that water is an indicator of life. It is a necessity for terrestrial life, but why does everyone assume that other forms of life in the universe would resemble us? Why do we assume that they would need water, oxygen, and carbon?

Because if we were ever to go to Mars, water has a ton of potential uses, and the fact that people need it survive... well, if it's already there, that would reduce a TON of weight, and because of that, greatly reduce the cost. Not to mention the uses for fuels, and things like that. Just because it's a "simple chemical substance made out of very abundant elements" doesn't mean that it's not something that's very useful. If you're curious, my chemistry professor spent a whole class talking about getting to Mars, and water was a huge part in that. I can talk about it more later, but I have to go to sleep for a calc review at 7 tomorrow.

I heard that show sucks, I could never make it through a single episode.

Yea just because Mars has water does not mean life exists or life has ever exists. We earthlings are obviously going to have somewhat of a bias when it comes to water considering creatures on this planet are made up of mainly water and then carbon based things. So we are going to think for other life they need water as well.

Unfortunately that isn't a very strong argument because just because we are made up of water doesn't mean life necessarily requires it. Hell life might be something we haven't even thought of or something we may not even consider "life" at first glance.

As for colonizing another planet, then indeed water would be a requirement for us to live on so that is good for us to eventually set up livable areas on Mars which we will eventually do.

The thing about Mars is that it has all the right ingredients for life, but the catalyst (water) is frozen or underground. There is plenty of evidence that water existed on Mars once (canyons that have clearly been etched out by water, etc...) and so I believe it is totally plausible that life once existed there.

But I think with the atmosphere being a near vacuum (600Pa to Earths 100,000Pa) and the lack of surface water that it is unlikely we will find life. Perhaps you may find archaeological evidence for life frozen in the soil, or life may still exist underground, but we may never know within our lifetime I'm afraid.

Also Mars's methane is like 10PpB, it's an incredibly small amount, especially seeing as the Martian atmosphere is so thin. If it does point to life, then it doesn't point to much life I would imagine.

The importance of water is not that creatures are made if it, but that it is an inert liquid so that organic molecules and all the other biological stuff that makes life have a chance to float towards each other and react. To form life without water you would need to find another type of inert liquid to host the beginnings of life.

Titan has entire lakes made of hydrocarbons, even though this wouldn't offer a particularly stable liquid for life to form it is still one of the most likely places to find life in our solar system because it offers some kind of host for life to form in.

Yeah water is a pretty neat liquid for life to form, it isn't an absolute necessity nor is it an absolute indicator of the existence of life, but a planet with large bodies of water would be closest to our idea of abiogenesis.

Also carbon based life isn't necessarily the only form, silicon also its a possibility. Other than that though there doesn't seem to be another element able to form the complex chains that would seem necessary for life to form.

Water is by far and away the most common liquid in the Universe as it is made up of two of the most common elements (Hydrogen and Oxygen), but other liquids are hypothesised to have a similar effect as water, such ammonia. A gas, a solid or an extremely unstable liquid would not offer a good place for life to form.

Silicon life is a possibility, but as far as I'm aware it can't get too complex due to the way reacts with many elements.

Actually this link has some good information about this

The first epsisode was interesting, but afterward it was the same old crap you see everywhere else.

I have taken Biology and while most people consider them life i don't. They don't even have a brain so they can't think.